完成句子（共3小题；每小题1 分， 满分3分）

1. 他的朋友患有头痛好多年了。

His friend has been_________ _________ headaches for some years.

2 我们必须利用每一分钟去学习

We must ______ ________ ________ every minute to study.

3 他因为腿不方便而行走缓慢。

He walked slowly_______ _______ his bad leg.